CODEWITHSUNDEEP
phpregex
Phil
Phil

Reputation: 1849

How to get specific substring with regex

I'm trying to extract and return the substring from a string which looks like this:

Array ( [query] => Array ( [normalized] => Array ( [0] => Array ( [from] => lion [to] => Lion ) ) [pages] => Array ( [36896] => Array ( [pageid] => 36896 [ns] => 0 [title] => Lion [extract] => The lion (Panthera leo) is one of the four big cats in the genus Panthera and a member of the family Felidae. With some males exceeding 250 kg (550 lb) in weight, it is the second-largest living cat after the tiger. ) ) ) )

The specific substring I need is always located between [extract] => and )))). I'm pretty bad at regex, and would appreciate any help!

I tried

preg_match('/\[extract\] =>(.*?)\)\)\)\)', $c,$hits);

and some other stuff, but nothing worked...

EDIT: Here's the full code I'm using:

$url = 'http://en.wikipedia.org/w/api.php?action=query&prop=extracts&format=txt&exsentences=2&exlimit=10&exintro=&explaintext=&iwurl=&titles=lion';

$ch = curl_init($url);
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt ($ch, CURLOPT_USERAGENT, "TestScript"); // required by wikipedia.org server; use YOUR user agent with YOUR contact information. (otherwise your IP might get blocked)
$c = curl_exec($ch);

preg_match('^.*\[extract\].?\=\>.?(.*).?\).?\).?\).?\)$', $c,$hits); 

print_r ($hits);

Upvotes: 0

Views: 90

Answers (4)

hwnd
hwnd

Reputation: 70732

Well considering that in both of your examples you are missing pattern delimiters, indeed it will not work as expected. Also you need to to match multiple accounts of whitespace to get back your desired result.

preg_match('/\[extract\]\s*=>\s*(.*?)(?:\s*\)){4}/i', $c, $hits); 
echo $hits[1];

Output

The lion (Panthera leo) is one of the four big cats in the genus Panthera and a member of the family Felidae. With some males exceeding 250 kg (550 lb) in weight, it is the second-largest living cat after the tiger.

See live demo

  • Regular expression:

    enter image description here

Upvotes: 2

Steve Pettifer
Steve Pettifer

Reputation: 2043

If you really must use regex (and as @JavierDiaz says it seems like overkill) then you could use this:

\[extract\](.*?)\)\s\)\s\)\s\)

Your example appears to have a space between each closing parenthesis at the end of the string - I'm not sure if that's intentional or not. If not, remove the \s bits.

The basic explanation is this:

\[         A literal '['
extract    A literal string
\]         A literal ']'
(          Start of capturing group
.*?        Any characters, any number of repetitions but as few as possible (non-greedy)
)          End of capturing group
\)         A literal ')'
\s         Any whitespace
\)         A literal ')'
\s         Any whitespace
\)         A literal ')'
\s         Any whitespace
\)         A literal ')'

you can try it out using Expresso or any other free RegEx editor (lots of them about).

EDIT: I knocked this up before an edit to the OP's question which adds that the => should not be included. Changing the start to \[extract\].+?\s(.*?) would do the trick, but this has been covered much better by Michael Perrenoud in another answer.

Upvotes: 1

Mike Perrenoud
Mike Perrenoud

Reputation: 67898

This will do the trick. You're looking for the string extract first, then you want to get to the start of the text with .+=>\s, then you'll grab all the text (.*?) in a non-greedy fashion until you find the end of the string with \s\)\s\)\s\)\s\):

extract.+=>\s(.*?)\s\)\s\)\s\)\s\)

Regular expression visualization

Debuggex Demo

As stated by Javier in Steve's post, you could also do this:

extract.+=>\s(.*?)(?:\s\)){4}

Regular expression visualization

Debuggex Demo

Upvotes: 1

moped
moped

Reputation: 2247

just because it's really funny how you want to solve this, here is regex (edited so there can be whitespace or not between ) ):

^.*\[extract\].?\=\>.?(.*).?\).?\).?\).?\)$

but you should definitelly use array functions to get to [extract] field and you will get it's content which is the part you want

tested here: http://regex101.com/r/qO5vO0

for php:

preg_match('/.*?\[extract\]\s\=\>\s(.*?)\s\)\s\)\s\)\s\)/i', $c, $hits);

echo $hits[1]; //outputs captured string

Upvotes: 1

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